Update error message in SearchEngineAdapter.

This aims to determine if the search engine is null or
some actual value.

BUG=944767

Change-Id: I7145903f77c0722fe1846f4b17a0ea9ea36f3a77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881969Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710060}

chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEngineAdapter.java

@@ -201,8 +201,9 @@ public class SearchEngineAdapter extends BaseAdapter
         }
 
         if (mSelectedSearchEnginePosition == -1) {
-            throw new IllegalStateException(
-                    "Default search engine index did not match any available search engines.");
+            throw new IllegalStateException("Default search engine, "
+                    + defaultSearchEngineTemplateUrl
+                    + ", index did not match any available search engines.");
         }
 
         mInitialEnginePosition = mSelectedSearchEnginePosition;